2017-02-21, Version 4.8.0 'Argon' (LTS)

Notable Changes:

* child_process: add shell option to spawn() (cjihrig)
  #4598
* crypto:
  * add ALPN Support (Shigeki Ohtsu)
    #2564
  * allow adding extra certs to well-known CAs (Sam Roberts)
    #9139
* deps:
  * v8: expose statistics about heap spaces (Ben Ripkens)
    #4463
* fs: add the fs.mkdtemp() function. (Florian MARGAINE)
  #5333
* process:
  * add `externalMemory` to `process` (Fedor Indutny)
    #9587
  * add process.cpuUsage() (Patrick Mueller)
    #10796